1. Field of the Invention
This invention is related to oars, paddles and the like which are used to move forward and backward any and all vessels over water, even if they have any type of engine.
2. History of the Prior Art
Oars, paddles and the like usually comprise a shaft having an integral blade at one end thereof which, when the oar is moved through water, with the blade disposed at right angles to the direction of movement of the oar, causes a reaction which propels the boat.
At the end of each such stroke or movement of the oar or paddle, it is lifted out of the water, returned to its initial position and the propelling stroke repeated.
It would be desirable, and would reduce the energy used by an operator, if the oar or paddle blade could remain immersed in the water during the return stroke, but with oars or paddles constructed as described above, this would not be possible because of the resistance of the water on the integral blades.
It has previously been proposed in Canadian Pat. No. 262860 (Beebe) to construct an oar in which the blades are pivotally mounted on a frame attached to a shaft, the frame member being constructed such that when the blades are moved to a position at right angles to the direction of movement of the oar by the resistance of the water, they are retained in the divergent position. In addition the frame includes stop means positioned so that during the return stroke of the oar with the blades still in the water, the blades will be moved into engagement with the stop by the resistance of the water so as to lie parallel with each other.
It has previously been proposed in U.S. Pat. Nos. 427,842, 1,066,662, 1,555,097, 1,805,749, 3,135,977, 4,622,017 to construct an oar or paddle having pivotal blades, in which the means for pivotally supporting the blades and for limiting the pivotal movement are formed integrally with the shaft.
It has previously been proposed in U.S. Pat. No. 7,309,364 to construct a flat substance which can be easily and more conveniently stored within small areas of most any water craft before being folding assembled.
The main disadvantage of devices designed according to patents mentioned above is that they are geared for a sole usage of an operator's manual energy and cannot sustain higher energy and larger vessel size requirements for motor and oar operated vessel designs. It is so because a pivot cannot physically sustain higher pressure and will break.
A second disadvantage is that boats operated with devices designed according to the above mentioned patents can move only forward, and do not have modes of moving backwards or braking. It must be stressed that having all three modes of forward, backward and braking is a vital feature for all vessels.
Therefore above mentioned patents can not be used at all for any motor-operated and large size vessels.